Struts2学习笔记——ActionWildcard(通配符)

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使用通配符可以将配置量降到最低。但是一定要遵守“约定由于配置”的原则。

Struts.xml：

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN""http://struts.apache.org/dtds/struts-2.3.dtd"><struts>  <constant name="struts.devMode" value="true" />  <!-- 通配符的使用 -->  <constant name="struts.enable.DynamicMethodInvocation" value="false" />   <package name="user" namespace="/actions" extends="struts-default">        <action name="Student*" class="com.smile.struts2.front.action.StudentAction" method="{1}">            <result name="success"> /Student{1}_success.jsp  </result>        </action>                <action name="*_*" class="com.smile.struts2.front.action.{1}Action" method="{2}">            <result name="success"> /{1}_{2}_success.jsp  </result>        </action>    </package></struts>

在这个配置中我们可以看到在配置StudentAction的时候使用了一个通配符来匹配Action的name。

<action name="Student*" class="com.smile.struts2.front.action.StudentAction" method="{1}">            <result name="success"> /Student{1}_success.jsp  </result>        </action>

表示如果我们的action是Studentadd则这里的method = “add” 返回指向的jsp文件就是Studentadd_success.jsp。

<action name="*_*" class="com.smile.struts2.front.action.{1}Action" method="{2}">            <result name="success"> /{1}_{2}_success.jsp  </result>        </action>

这个配置中使用了两个占位符。如果name = "Teacher_add" 则对应的class = “com.smile.struts2.front.action.TeacherAction” method = "add" 返回指向的jsp界面就是Teacher_add_success.jsp。

增加三个action类来处理：

CourseAction：

package com.smile.struts2.front.action;import com.opensymphony.xwork2.ActionSupport;public class CourseAction extends ActionSupport {//public String execute(){//return "path";//}public String add(){return SUCCESS;}public String delete(){return SUCCESS;}}

TeacherAction：

package com.smile.struts2.front.action;import com.opensymphony.xwork2.ActionSupport;public class TeacherAction extends ActionSupport {//public String execute(){//return "path";//}public String add(){return SUCCESS;}public String delete(){return SUCCESS;}}

StudentAction：

package com.smile.struts2.front.action;import com.opensymphony.xwork2.ActionSupport;public class StudentAction extends ActionSupport {//public String execute(){//return "path";//}public String add(){return SUCCESS;}public String delete(){return SUCCESS;}}

index.jsp：

<?xml version="1.0" encoding="GB18030" ?><%@ page language="java" contentType="text/html; charset=GB18030"    pageEncoding="GB18030"%><% String context = request.getContextPath(); %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030" /><title>Insert title here</title></head><body>使用通配符，将配置量降到最低<br /><a href="<%=context %>/actions/Studentadd">添加学生</a> <!-- Studentadd_success.jsp --><a href="<%=context %>/actions/Studentdelete">删除学生</a> <!-- Studentdelete_success.jsp --><br />不过，一定要遵守"约定优于配置"的原则<br /><a href="<%=context %>/actions/Teacher_add">添加老师</a> <!-- Teacher_add_success.jsp --><a href="<%=context %>/actions/Teacher_delete">删除老师</a> <!-- Teacher_delete_success.jsp --><a href="<%=context %>/actions/Course_add">添加课程</a> <!-- Course_add_success.jsp --><a href="<%=context %>/actions/Course_delete">删除课程</a><!-- Course_delete_success.jsp -->    </body></html>

这样就可以使用通配符减少在Struts.xml中的配置。

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